Calculating machine



Feb. 6, 1923. 1,444,478

F. o. MUELLER CALCULATING MACHINE Filed Apr. 11, 1921 `6 sheetssheeb 2 F. O. MUELLER l CALCULATING MACHINE Filed Apr. ll, 1921 6 sheets-sheet 8 Feb 6, 1923.

F. O. MUELLER CALQULATING MAcHIrxE 6 sheets-sheet 4 Filed Apr. H 1921 .Zweniar Xwxx N26. wbk

R 56K/M wia/maza y F.0.MUELLER QALCULATING ywmcmm:

` 6 sheets-sheet 5 Feb. 6, 1923.`

Fllgd Apr. 11, 1921 L 175." T s@ Willmss Feb. 6, 1923.'

F. O. MUELLER [mmmmpvY MACHINE Filed Apr. ll, 1921 6 sheets-sheet G Patented Fel). 6, 1923.

UNITED STATES PATENT OFFICE.

FREDERICK GTTO MUELLER, 0F ST, LOUIS, MISSOURI, ASSIGHGR, BY MIBNE ASSIGN- MENTS, TO BURROUGHS ADDING MACHINE COMPNY, AiCORPORATION 0F MICHI- GAN.

CALCULATING MACHINE.

Application tiled Aprlvll, 1921. SeriallNo. 460,254.

To all iran/m. itt/n all] cri/mem J Be it known that l, l `iisiiizuicii O'rro Mumia-m, a citizen of the United States, re` siding at St. Louis, Missouri. have invented a certain new and useful Iiiiproiciiicnt in Calculating Machines, ofuliicli tlieufollovvingr is a fu'll, clear, and exact description. such as will enable others skilledl in thev art to. which it aippertains to make` and use the same. reference being had to the accompanying drawings, forming part of this applica,- tion. l V'lliis invention relates to. new uiid useful improrements in calculating l iiiarliines. .the oli'ectl ,being .to providiineiinsvifoi' rompelling the completion otv thefiniilt-iplvin r operations und for locking the istepac and release mechanisms so that tliere'airtoftalizer wheels can notl he I'shifted laterally during the calculating operationsof the machine` and is'designed piiijticu'larlys:in improvement on4 calculating machines of the. type disclosed in United States I .Vetters.lfiit ent No.- 1,317,604, dated September 3(llv 919, and United States Letters Patent No. 1,336,904, dated April 13, 1920. In multiplying o ierations of tliercalculoting machines of tie type diselos'eddn the above patents, the machine is givengtwo complete opei'ations, the tens multiplying plates being actuated during the first operationto introduce into the rear totalizeis the tens partial product and the units multiplying plates being actuated during the second operation to register the units partial products. v

The machine. is operated Lly a-rriotor which is adapted-to be thrown intoland vout ofen.- gagement with the actuating mechanism of said machine by a vertically moviihle clutch operating bar having a laterally projecting pin in its u per end. The ends of this pin occupy note es formed in the upper edges of longitudinally movable bars horizontally dis `osed on each side of the upper end of sai Avertical bar, one of said barsbeing nda ted to be operated b thedepression of the multiplier keys ,an the other being adapted to be actuated by the Adepression of the motor key.

` en either the l or the zero multiplier key is struck, the Corresponding longitudinal bar is moved forwardly causing tlie pin in the'upper end of the-vertical-clutel1 yclutch operatingbnr operating'ybar Ato ride upon the rearwardly inclined portion of the notch, thereby raising said clutch bar and throwing the motor into engagement Vwith the actuating mechanism Ofthe machine. The forward movement. of the longitudinal bar will bring the straight np'pervedge 4thereof under the pin and hold the clutch bar against downward movement until the longitudinal bar is released and .restoitedto its Vnormal. position just before 'the operiitiiig shaft completes a. single stroke., lien ,theffor any multiplier key of Vhigher digital order is depressed, the motor ,will `through suitable mechanism causethe operating shaft ofthe machine to he giyeiiihw lc :onplete operations with the exception 4of the, l key and the zero key, these causing tlieimotor to drive the operating: shaft only one complete revolution. Inthe actual 4u sepof the machine, the multiplierv keyslare sometimes whipped vor struck quickly so that the longitudinal bar is Inet. moved forwardly a sufficient distanee tdposition `the pin on the straight edge thereoin Which case the pin carried by the returns immediately to its position in the notch, so hat the motor, `While,effecting' a single stroke of the operating Shaft, is disengaged before the rzictuatin 4mechanism `of the machine is given its ppssiiily intended two complete operations.

ln order to compel the longitudinal bar to move forwardly the full distance and retain' the pin of the clutch operating bar in its-operative position for theJ Second multiplying operationV of the machine, when riecessiiry,lthe present invention contemplates a mechanism operable by the operation of the tens plate,. ivliich mechanism is set in position so as to prevent return movement of the longitudinal bar until the machine has been insured of the completion of its multiplying operations. i Y

`Another object of the invention is to pro.-l

mentofvthe totalizer shaft to be released so as to allow the reartotalizer wheels to be shifted laterally to their normal or home sition at the right side of the machine. Vhen the step-back key is operated, the rear totalizer wheels are caused to return one step at each operation thereof toward the. normal position at the right. In order to lock said keys. the locking means cooperate with the step-back and release mechanisms and hold them inoperative during the multiv plying operations. This locking mechanism is operatively connected with the longitudinalhar so that the depression of any multiplier key will cause said locking means to disable the stepback and vrelease mechanisms. f

Figure 1 is a skeletonized view of the machine showing in full lines the longitudinal bar operated by the multiplier keys and the locking mechanism for the release and step-back keys.

FigureA 2 is a top plan view of the front and rear totalizers and their carrying frames. Figure 3 is a detail perspective view of one of the multiply-ing keys and its connections.

Figure 4 is a detail view ofV the stepbaek and release keys.

Figure 5 is a detail view of the rear portion of the machine showing the location of the multiplying section.

Figure 6 is a vertical cross-section through the multiplying section showing one of the tens multip ying plates in raisedposition.

Figule? is afhorizontal cross section online 7 7 of Figure 6. S

Figure 8 is a side elevation of the locking mechanism for the stepllmckand release keys and showing the parts thereof ready for the irst operation and after a multiplier key has been depressed. e

Figure 9 shows the position assiimed by the parts shown in Figure 8 during the first half of the second operation. V

Figure 10 is a plan View of parts shown in Figure 5 in normal position.

Figure 1l is u plan view of parts shown in Figure H. 1

Figure 12 is a plan view of'parts shown in Figure 9.

Referring by numerals to the accompanying drawings, 1 indicates the frame of the I machine, the keyboard of which is equipped with the usual adding keys 2 and multiplier keys 4. The latter when depressed operate hell-cranks 5 which are :onnected by' rods 6 to horizontally disposed liars 7 which extend rearwardly under the vertically disposed units multiplying plates 8 and'tens multiplying plates 9. he rearends of bar 7 which pass beyond plates 8 and 9 are provided with upwardly presented extenslo'ns 1() having vertically disposed notches 10". (lccupying each notch 10" is a pin 11 projecting laterally from the lower end of the pawl 12 which is mounted for rocking mover ment on the horizontally disposed rod 13. the latter heilig carried by side walls 14 of the multiplyimr section. Normally. the upper end of earl pawl l2 is held under the rearwardly extending arm of the hell-crank l5 and prerents the downward movement there of. One of these bell-cranks is pirotally supported on.each tens multiplying plate 9 and is pressed downwardly bv thefree end. of a spi-ing 14 carried hy each plate. Each pawl 12 has a rearward extension to which 1s connected spring 1G which tends to hold said )aulin engagement with the 'corrov spout mg hell-crank 15 whereby said bellcrank is held in inoperative iosition.

Adjoining each pawl 12 an pivotally sup! ported on rod 13 is a pawl 17 haring a shoulder 18 which is normally held by aspring 19, connected to each pawl, under the horlzontal arm of a bell-crank 20, the `latter beL ing pivotally supported on aunitlnultipl ing plate 8. The upper ends of the pawls i7 extend upwardly a predetermined distance above the bell-cranks 20 and are provided with projections or-pins 21.. A pawl 17 having a pin 21 is provided for each unit multiplying plate, except' the zero and 1" plates w ich are operated b the depression of the zero and 1 multip ying keys. Each pin 21 lies in the path of upward movement of a heel portion 9a extending' rearwardly from a corresponding tens multiplying plate. A spring 22 is connected with each pawl 17 and tends to hold shoulder 18 in engagementy with the corresponding bell-crank 20. A

Yhorizontal bar 24 is arranged for vertical movement in the side walls 14 of theV multiplying section and normally rests below the lower ends of crank arms 15 and 20. One end of said bar 24 extends through the side wall 14 and is connected by a link 25 to an arm 26 which is fixed to shaft 27, the latter being suitably journaled on the base of the machine. A pinion 28 is fixedly mounted on shaft 27 and meshes with asegment 29` arranged to receive rockin motion through suitable connections (nots own) which connections operatively connect the segment with the motor. i

Each har 7 is provided with an upward projection 7 the forward edge of which ears against one end of a toggle joint consisting of a rearwardly extending plate 31, the forward end of which is pivotally moun yd in bearings formed on the base, while the rear end is pivot/ally conne `ted to the lower end of plate 32. Plate is inelined rearwardly and its upper ent contacts with theextensions 7 on each har 7. A bar 34 is longitudinally disposed on the base of the machine adjacent 'to segment 29 and its .rear end 35 extends upwardly and is provided with a notch 35a in which is po sitloned a piu 3G, the latter projecting from one side of plate 32. Bar 34'is slidable in its bearings and its upper edge is provided with a notch 34?. havin an upwardly incllned face. Oocupyingt is notch is av transverse vprin 37 fixed in the upper end of a motor clutch operating bar 38.

Pivotally mounted on--the side walls 14 above'lpawlslQ and 1i' is a. horizontally disposed member39`v having an inwardly projecting portion 39* which lies in thepath of upward movement of `heel-portions 9 on plates 9. Rocking member 39 is connected by a link v40. to "i1V bell-crank 41 pivotally mounted in the lower'portion of one of the side walls14..'Aforwarclly extending bar 42 ispivotally onneeted at its rear end lo hell-crank 41-'andi`s provided at itsforvvanl end with a.' hrizoritallv disposed pin fl-l- 'which is designedjto bear against the rear ed of projection@ l: theniultiplying loperation of the inach'i'ne, Vthe depression of any 'one of the multiplier keys :will move its Corresponding ba r 7 V'forwardly' rocking-lpwl'IQ, thereby releasing its'fiorresponding bell-crank l'so .thnltits'lower end will be'i'rlov'ejrl outwardlyr and forwnjdly"by spring'Hinto a posit-ion` whereit can be"ngaged by the upwardly operating bar24; that the'tensmultiplying plate on' which 'said bell crank is mounted Awill be raised' into operative position.

i Simultaneously upward projection l" on the actuating-han( 'strikes the upper end of plate 32,moving'it andjpin 36 carried there- 0n and occupying.notch 35- in the-rear end of bar 34 forwardly. The forward movement.of bar 34 causes 4pin 137 in the upper end of-barl 3S-to ride upon the inclined portion of notch 3-4 and rest on the straight upper edge of bar 34. =The upward movement of bar 38 connectsthe motor to the actuatingln'iechanism of the machine so that segment 29 is 'rocked on shaft 30 thereby imparting' rotary motion to shaft 2T. Arm 2G carried by .said shaft causes bar 24 to which itis operatively connected by 'arm 2 to move upwardly. ln its upward movement bar 24 will engage the lower end of the released bell-crank lever l5 and carry it and its corresponding lena` multiplying plate upwardly.

The zero and `1 tens multiplyingr plates, cach requiring only one-'operation of the machine. arc not provided with heel portions 9, so that roc-king member 39 is not affected by their operation, and. consequently. pin 44 is not moved forward'. 'lhe remaining tous multiplying plates being provide-d with heel portions 5), their upward movement will bring their (forlvsqiondiupr heel portions against the inwardly projectin;r portion 39 and cause member Il!) to rorlt ou its pivots. This rorking;r motion will br imparted to bell-crank -ll through link -lll musing it lo more bar 4i! forwardly. lin

Mpc-arried by the forward end of link-"l2 is moved forward a. predetermined distance and being positioned immediately behind the naar end ofbar34 will compel said `bar to 'travel its full distance forward so. tllat pin 37 is properly positioned-on thestraigbt upper end of baril-t and .is caused to remain in this position until bar 34-isreleased by suitable mechanism; not-shownLtbereby insuring the' second operation-of the machine` which is necessary in completingthe multi'- plying operations. When-bar-34 is released vmachineundadiacent to release key 45..;1nd

operates.` bell-crank -52 .which is -oonuerted by'lod 541.0 arm 55, the -la-tterbeing fixed to -shaft A `vert icn.llj,f movable rocking bar 5,6 is-conueoled at its lower endto .ar'iu 57 which is fixed to shaftl :und the upper end ofsaid banis adapted to operate pawls 58,V saidpawlsbeiug adapted to cooperate` with escapementteeth onshaftV 4T; Av Vhen the step-back key Ais depressed. bar 5691301'- ates -pitwls 58 so as to .permit shaft-.47 and the -totalizer wheels carried thereby to step ll'aek one spruce towards `the .right 'or normal position.

Arm 59, is conjoined to arm 5 dan'd is connected :to lever 60 by-rod 61. lfVhen the release kel is operated, lever 60 is actuated by said y -to roclr arm 56 and -cause it to operate pawls 58 to release shaft 47 and permit it to return to its home position. In Figure 4 the step-back key is shown 4dc,- pressed, and' in Figure 5 arms 55 and 57 arc shown in moved position being operated by the depressiouof the step-baekkey.rand bar 5G is raised so that'escapement pa-wls 5R are thrown out of engagement with shaft '17, thereby releasing' same for movement one step back or towards its normal position. y

iivotally supported on the frame of the machine and rearwardly of arnis 55 and 5G is a pla-tfx 62 the forward end of which is bifurcatal to form extensions 62 and 62". Extensions 62* is locatedadjacent to the downwardly dependingarm 55, andits for ward end is bent downwardly `and normally is positioned above lateral projection 55 on ann 55, This projection can be formed bv ha\in, r the end of the screw which forms pirotal connection between rod 54 and arm .35 project outwardly a slight distance from arm 55. Similarly. the forward end of cxtension 62h is heut downwardly and is normally positioned above the lateral projection or screw 5U projectiupr from arm 5U.

(ln `thc underside of plate (i2 is pivoted the rear end of pawl 64, the forward end of which is adapted to normally rest on the upper portion of segment 29. A sprinpr (i5 connected to piLwl 64 tends to hold said pawl in a downward position. A horizontal lever" 6G is transreisely mounted on base 3 by pivotal' connection 67. The rear or innexI end of this lever rests against the rear cud of bar 34 and is yie-ldingly connected thereto by SprintsIr 68. one end of said spring being connected to pin (itl carried by said lever and the'otherend of said spring heini,r connected to pin 34" carried by bar 34. Tile outer end of lever (il) is bent` upwardly and pivotally mounted ou the upper end thereof is a tappet Tl) havingr its upper end beveled or inclined and normally bearingr against lapr T1, which lug is formed on the undeiside of plate62. Tappet 7U is held in engagement with iupr 7l hy a sprin,r T2 carried h v the lever 66 and connected to said tappeti. The forward end of pawl 64 rests on piu T4 projecting: latel` ally from tappet 7U. Pawl (34 is held downwardly by spring 65 and is provided with a shoulder T5 which is designed to engage. pin 74 and hold tappet TO in disabled position when lever 6G is actuated.

ln Figure 5, arm 55 is Shown move/d fol'- wardly and har 56 is raised to operate. escupeuient pawls 5S. \Vhen in normal position` arm 55 will be in alinement with arm 5U so that pin 55 carried by arm 55 and pin 50 carried by arm 50 are located rearwardly of the downwardly extendinar portions of extensions 62* and 6'2". `When plate 62 is released, these forward extensions more downuardly and their downwardly extendingr portions will be positioned in front of the pins 55 and 50". so that the forward or operating movement of arms and a5 is blocked, thereby locking the step-back and release mechanisms against operation. Normally` plate G2 and lever (i6 and parts assoc/inte therewith occupy positions as shown in *igures 5 and 10.

Then a multiplier key is operated. the. bar 34 is shifted forwardly, the inner end of lever 66 being connected to the rear end of said bar by spring 68, said lever will be operated to move its upwardly extendingr end rearwardly. This will cause the tappet pivotally mounted thereon to Vmove rearwardly and disengage its upper end from lug 71 so that pin 74 occupies a position immediately in tho rear of shouldor of awl 64, as shown in Figures 8 and ll. llate 62 being no longer held in raised position by tappet 7U, is pulled downwardly by spring 65 so that the projections 62*l and 62 will engage pins 55" and 50a carried by arms 55 and 50, respectively.

As before stated, in multiplying operations involving multiplier keys of higher denomination than zero and 1, the machine is required to perform two complete operations. ln order to hold the stepback and release mechanisms locked during the second operation, bar 34 and lever 66 being restored to their normal position at the completion of the first operation, pawl 64 is provided with a shoulder 75, which is adapted to engage piu 74 on tappet 70 and hold said tappet in disabled position during the second operation ofthe multiplying mechanism, as shown in Figures 9 and 12. Segment 29 is arranged to strike thevforward end of' pawl 64 and maintain it in a slightly raised position when said segment is in its home or normal position. Conse uently, when segment 29 is rocked downwaiidly during the first op-y eration, pawl 64 moves downwardly under the inHuence of springs 65 and engages pin 74 so that when lever 66 is restored, said pawl will prevent the return movement of the upper end of tappet 70 into engagement with the lug 71 on plate 62. Upon the completion of the multiplying operations, segment 29 is returned to its normal position and moves pawl 6l upwardly out of engagement with pin 74 so that tappet 70 is restored to its home position by spring;r 72. This restoration of tappet 70 brings the upper end thereof into engagement with lug 7l so that plate 62 is rocked upwardly and extensions 62 and 62 are raised out of en pagement with projections 55 and 50 therey releasing the arms 55 and 50 for operation.

lVhat I claim is:

l. In a calculating machine` the combinaition of multiplying plates, means for open ating said multiplying plates, and means positively operable by one of said multiplying plates for causing the first mentioned means to perform its intended operation.

2. In a calculating1 machine, the combination of a register, plates for obtaining: tens and units partial products, and introducing them into said register, means for operating said plates, and positive means for insuring necessary consecutive operation of said plates.

3. In a calculating machine, the combination of a product register, plates for introducing partial products thereinbo, and means controlled by the operation of one of said plates for positively insuring the operation of the other of said plates.

4. In a calculating machine, the combination of a product register` means for stepping the same progressivelyto higher denominations, means for restoring,r said regis ter to home position retrogressively` and a trap for controlling said means so that one means is locked against the movement of the other. l

5. In a calculating machine, the combination ofa product register, means for advancing the same to higher denominations,

`an eseapement mechanism .whiclrmay be` retion Aof .a multiplying plate, a 4,key for' lop erating the plate, a motor1 operatingbar .pty sitioned bythe key, landl meanscoutrolled by the plate for preventingrthe untimely resto- ,l

ration of saidinotorbar.I ,A l ,f

7. In aiealeulatmg macliine,lthe combina tionof amultiplying plate@ keyffor operating said plate, a motor operatingrbar, positioned byl the key, .and means op'eratil said platefor ycooperatingjvith,said Akey in positioningi said motor bar,l toffinsure the necessary sequential operations ofsaid'rna.- chine.

8. In aeavlculating mac'hiir'le, ,thel combinai tion of a powersliaft,multiplyinginecha-v u p v adiipted to` nio'vsadf link forwardly.

j 15.f In'Y h' ttlci'ilating machinm the 'combinism operable thereby, said` multiplying .mechanism including aproductregister, re-

vstoring means for'the product. register-,and means operable by the powergsliaft andin control ofsaid register restoingmeans `9. In a, calculating maehinetheombination of 4a key, motor drivenhinultiplying mechanism havinga product register, abar for controlling the motor drive of saidniulti plying mechanism and operatively positioned bysaid key returning means for the prod uct register, and means controlledby said motor bar for rendering inoperative said returningv means. Y Y

l0. In a calculating machine, Vthe combination of nmltiplying mechanism having laterally movable totaliz/.er wheels, escapement mechanism therefor,` and meansv operable by said multiplyingr nrxeclmnism for automatically locking said eseapement mechanism when said multiplying mechanism is actuated.

11. In a calculating machine, the combination of multiplier keys, totalizer wheels, an escapement mechanism therefor` a manu4 ally operable stepbaek ke) adapted to operate said escapement mechanism whereby said totalizer Wheelsaie returned to theiinormal position one step at a time` a manually op arable release key adapted to operate said escapeinent mechanism whereby said totalizer wheels are restored to their home position, and means operable by said multiplier keys for locking said step-back and said release keys against operation.

l2. In a calculaing machine. the combination of multiplier keys, multiplying mechanism including vertically movable plates, motor rengaging and disengaging means for said Vmultiplying mechanism, and means actuated by the vertical movement of said multiplying plates and adapted to compel said motor engaging and disengaging means to positively move into engaging position.

13. In a 'calculating machine, the combination of multiplier keys, multiplying mechamsin including vertically movable multiplying plates. motor controlling means, a pivotally 'supported 4transverse member adapted `tovbe jaetuated by vsaid plates, and nieansaetii'ated by said 'transverse memberand ulz'ipted'to positively hold said 4motor` lc'on'trolling means in operative position.y v

1.4. In afcalculating machine, the combination ofinultipli'er keys, multiplying plates j niovable in" vertical plane 'and provided l iv'ithfrerivardly 'projecting portions, a' lon- 4{,fitiiilxlnallyf movable bar for controlling the drivn'ig eonnection's'of the machine `and opA `erable `by said keys, a' pivot'ally mounted tuition of' multiplying plates movable in vertical 'plane and vhaving rearward lextensions, aokingplat pivotally moun'tedabove-aaid yextensionstliidfiidapted tto'be 'actuated thereaihoriaontal bar movablelongitudinali)4 "tolestablis'lidrivigconnections for said ina- Cliine," and a 'longitudinally movable link operable liysaid roi-.king'plate and adapted to positively position said horizontal bar in driving engagement.

16. In a calculating machine, the combi nation of multiplier keys, vertically mov- Aable plates provided with rear heel portions, a roc (ing plate positioned abovc'and in the path of movement of said heel portions and arranged to be actuated thereby, a movable har operable by said keys to establish driving connections for said machine,v and a movable member operable by said rocking plato for retaining said bar in operative position whereby theeompletion of multiplying operations is insured.

17.`In a multiplyingmechanism forcelculating machines, the combination of keys` multiplying plates movable in vertical plane. rearwardly projecting extensions on said plates. means operable by said keys for controlling the driving connectionsof said nml tiplying mechanism, and means operable by said extensions for preventing the return movement of said drive controlling means before the completion of the multiplying operations.

lh', ln a multiplying mechanism for calculating machines. the combination of verti cally movable multiplying plates. actuating mechanism therefor, means for controlling the driving connections of said actuating mechanism. a longitudinali bar movable in a horizontal plantl and adapted lo position said drive controlling means in operative position. a rocking member positioned in the path of movement of said multiplying plates whereby said rocking member is actuated, and means operable by said rocking member for positivelv blocking the return movement of said longitudinal bar.

lil. ln a calculating machine. the combina` tion of multiplier keys, a motor bar operable by said keys. multiplying mechanism iro` vided with laterally movable totallizer wheels` an escapement mechanism for .iermitting lateral movement of Suid totalizer wheels toward their normal position, and means for locking said escapement mechanisxn when the multiplying mechanism is actuated, said locking means being operable by the actuation of said motor bar.

2U. In a calculating machine, the combination of nniltiplier keys, a longitudinally movable motor bar operable by said keys, multi )lyingr mechanism having laterally mova ile totalizer wheels, escapement mecha uism for permitting the lateral movement of said tutalizer wheels towards their normal position, means for locking said escapement mechanism. a lever having cooperative counectiou with said motor bar and displaceable means associated with said lever and adapted to' normally hold said locking member inoperative. said displaceable means being arranged to be displaced when said lever is actuated whereby said locking member is rendered operative.

2l. ln a calculating machine, the combination of umltipliei' keys. multiplying mechanism having laterally movable totalizer wheels, a motor bar operable by said keys, escapement mechanism for said totalilzer wheels` step-back mechanism for actuating `said escapement mechanism whereby said totalizer wheels are shifted laterally one step towards their normal position, and locking means associated with said motor bar and adapted to lock said step-back mechanism when a multiplier key is operated.

22. .ln a calculating mach1ne,the combina` tion of multiplier keys, a motor bar operable by said keys, multiplying mechanism includinnr laterally movable totalizer wheels, step-back mechanism adapted to move said totalizer wheels one step towards their normal position, a rocking member for locking said step-back mechanism, a lever cooperating with said motor bar, and means adapted to move said *locking member into operative or inoperative position.

23. In a calculating machine, the combination of multiplier keys, a motor bar operable by said kevs, multiplying mechanism including intera ly movable totalizer Wheels` stephack mechanism adapted to move said totalizcr wheels one step towards their normal position. a rocking member, for locking said step-back mechanism, a` lever cooperating with said motor' bar. means pivtally mounted on said lever and adapted to move said locking member into operative or inoperative position. and a member adapted to engage said means and hold it in disabled position.

24. In a calculating machine,the combination of multiplier keys, u, motor bar operable by said keys, laterally movable totalizer wheels, escapement mechanism for said totalizer wheels, u release key for actuating said escapement mechanism whereby the totalizer wheels are restored to their normal position, a pivotally mounted plate adapted to be moved into operative position and lock said release key, a lever having yielding operative connection with said motor bar, and a displaceable member carried by said lever and normally in engagement with said plate, whereby said plate is rendered inoperative, said displaceable member being adapted to be moved b said lever out of engagenient4 with said plate, whereby said plate is rendei-ed operative to lock said release key. e

25. ln a calculating machine, the combination of multiplier keys, a motor bar operable by said keys, laterally movable totalizer wheels, escapement mechanism for said totalizer wheels, a release key for actuating said escapement mechanism, whereby the totalizer wheels are restored to their normal position, a pivotally mounted plate adapted to be moved into un operative position and lock said release key, a lever having yielding operative connection lwith said motor bar, a displaceable member carried by said lever and normally in engagement with said plate, whereby said plate is rendered inoperative, said displaceable member being adapted to be moved by said lever outl of engagement with said plate, whereby said plate is rendered operative, and means for retaining said displaceable mem'ber in disengaging po` sition.

In testimony whereof I hereunto atiix m signature this 7th da of April,'1921.

FREDERICK TT() MUELLER. 

